Association Between Spontaneous Echo Contrast and Mitral Valve Area in Mitral Stenosis: A Cross-Sectional Study

Abstract

Objectives: This study aims to investigate the relationship between mitral valve area (MVA) and spontaneous echo contrast (SEC) in patients with mitral stenosis (MS). Additionally, it explores the association between SEC and other echocardiographic parameters of MS hemodynamics, which may serve as important markers of thrombogenesis. Since the presence of a left atrial (LA) thrombus significantly influences surgical, diagnostic, and therapeutic decision-making, early detection of SEC could facilitate timely intervention and anticoagulation strategies. Methodology: This observational cross-sectional study was conducted in the Cardiology Department of Gulab Devi Teaching Hospital, Lahore, Pakistan, from September 2023 to February 2024. The study included patients with severe MS who underwent transesophageal echocardiography (TEE) and were eligible for percutaneous transluminal mitral commissurotomy (PTMC). Baseline electrocardiography (ECG) was performed to assess heart rhythm. A single observer conducted all echocardiographic evaluations to eliminate interobserver variability. SEC was classified into four grades: Grade 0 (no contrast), Grade 1 (mild echogenic swirling), Grade 2 (dense swirling), and Grade 3 (intense swirling). Results: A total of 100 patients with MS were included, with a mean age of 34.54 ± 10.42 years. Based on the presence or absence of SEC, patients were divided into two groups. Group 1 (n=72) had a mean MVA of 0.76 ± 0.20 cm², while Group 2 (n=28) had a mean MVA of 1.26 ± 0.27 cm². The Mann-Whitney U test demonstrated a significant association between SEC and MVA (p = 0.001). Additionally, SEC was significantly associated with atrial fibrillation, LA area, left atrial appendage flow velocity (LAAFV), mitral valve pressure gradient (MVPG), and pulmonary artery systolic pressure (PASP), whereas no significant relationship was found with left ventricular ejection fraction (LVEF) or left ventricular fractional shortening (LVFS). Multivariate regression analysis confirmed that SEC independently influenced MVA and other echocardiographic predictors of MS (p = 0.001, effect size = 0.735 [73.5%]). Conclusion: SEC was more prevalent in patients with smaller MVA and atrial fibrillation, whereas those with larger MVA and sinus rhythm had a lower incidence. Its presence was correlated with LA enlargement, reduced LAAFV, elevated MVPG, and increased PASP but did not impact LVEF or LVFS. As a marker of blood stasis and a prothrombotic state, SEC necessitates a proactive anticoagulation strategy to mitigate thromboembolic risk in patients with MS.